Abstract

CMOS pulldown networks are characterized by their switching energy (E)
and propagation delay (t), and voltage scaling has been shown to allow
E or t to be adjusted, while Et^2 remains constant. Previously, this
argument about single pulldown stages was applied to arbitrary digital
circuits by assuming that the total delay of any such circuit was a
sum of single pulldown and pullup stage delays, neglecting the time
variation of the input to each stage. In this paper, the statement
that Et^2 is independent of voltage scaling is generalized to
arbitrary networks of CMOS transitors using only a weaker assumption:
that every node has a capacitance.